The term wastewater includes sewage and other water that has become contaminated with chemicals or other materials rendering such water unsafe for disposal without treatment. One universal and serious form of water contamination is non-point source pollution (NPS). An example of NPS is urban runoff, wherein rainfall or snow-melt transports widespread, low-level pollutants from surfaces to catch basins connected to below-ground storm water drainage systems that in turn ultimately migrate to neighboring environments such as ponds, marsh or streams. Wastewater remediation treatment strategies are frequently combined with scheduled maintenance programs in order to slow the unwanted accumulation and dissemination of contamination.
Common systems such as floor drains located in areas used for activities such as health care or food processing and preparation are particularly troublesome due to occurrences of food born disease caused by psychotropic, pathogenic microorganisms known to breed in such drains.
Bioremediation is the term given to treatment processes that utilize microorganisms for the digestion or biological degradation of hazardous substances to produce substances that are less toxic or nontoxic. Bioremediation protocols have been extensively and successfully utilized in the treatment of many types of aqueous waste. Microbial agents known to have bioremedial utility in controlling organic and inorganic contaminants found in aquatic or terrestrial environments include bacteria, algae, fungi, yeast, protozoa and the like as well as cell-free extracts of such organisms and combinations thereof. Several commercial bioremediation preparations utilizing naturally occurring microorganisms alone or in combination are readily available for the degradation of a variety of pollutants such as herbicides and other agricultural chemicals, industrial solvents and cleaners, medical waste, and various other products found to be environmentally hazardous. Furthermore, advanced technologies for selection, isolation and attenuation of the remediation effectiveness of useful bioremediation organisms have steadily and substantially improved over the past two decades. Bioremediation can also be used in conjunction with a wide range of physical and chemical technologies.
In addition to readily available commercial bioremediation preparations, many microorganisms determined to be useful in bioremediation systems have been recently identified, isolated and cultured. For example, U.S. Pat. No. 6,194,197 to Hyman et al. discloses a Graphium sp. fungus capable of co-metabolizing the common gasoline additive; methyl tert-butyl ether (MTBE). U.S. Pat. No. 6,096,530 to Kato et al. discloses a strain of Pseudomonas cepacia isolated from termite intestine that degrades the water-contaminating industrial degreasing solvent trichloroethylene (TCE) as well as various furan compounds.
Also available for use in waste treatment systems are strains of genetically modified microorganisms which are capable of degrading numerous environmentally persistent waste chemicals such as pesticides, herbicides, fire retardants, propellants, and the like which have been described over the past twenty years. For example, U.S. Pat. No. 4,535,061 to Chakrabarty et al. describes modified strains of Pseudomonas cepacia: that degrade polychlorinated biphenyls (PHB's). More recently, U.S. Pat. No. 5,578,474 to Focht et al. describes construction of new recombinant strains of microorganism genera such as Pseudomonas, Alcaligenes, Acinetobacter or Arthrobacter, which are useful in the disposal of toxic waste such as chlorobenzene. Furthermore, such modified organisms can be produced in quantity by commercially useful processes.
It is well known in the art that contaminant reducing agents, including microbial agents useful in the control of both organic and inorganic contaminants in aquatic or terrestrial environments, are often immobilized by inoculating or affixing to an appropriate immobilizing support medium. Suitable immobilizing media include, but are not limited to, woven and non-woven scaffolding; natural and synthetic matrices; high surface-area inert solids; and other materials containing voids and channels in which the agents can reside. Such materials are easily obtained and many commercial bioremediation preparations utilizing immobilizing media are commercially available.
In order to be effective in bio-remediation a treatment system must be capable of maintaining a sufficient concentration of active, healthy organisms throughout the process. Therefore, effective systems for bioremediation must be capable of delivering measured quantities of treatment agents, including microorganisms, continuously at a predetermined rate over time. Incremental release has shown to be useful when establishing the biomass augmentation that is important to a successful bioremediation treatment strategy. Treatment systems that rely on manual delivery of remediation formulations are generally ineffective. For example, U.S. Pat. No. 5,225,083 to Passas et al. discloses a method for bioremediation of grease traps involving a periodic manual delivery of a bacterial remediation agent along with other additives. Such manual methods have numerous associated drawbacks including inappropriate agent levels and incorrectly timed scheduled for release. Furthermore, these manual delivery methods are particularly ineffective when the system encounters temporary fluctuations of pH in the wastewater stream. Also, these methods can result in a condition wherein bacterial media delivered as a bolus receive inadequate oxygen and/or nutrients.
A variety of direct contact methods for the continuous dispensing of remediation agents into waste streams have been described. A system for seeding bacterial cultures to a waste stream is described by Hater et al. in U.S. Pat. No. 4,810,385. The system utilizes a simple device consisting of a textile package or sock filled with dried bacterial cultures or microorganisms suitable for degrading waste. In use, the sock is immersed in a waste stream and as sewage flows through the sock the dried bacteria are wetted and released into the stream. Another direct contact device for bioremediation of waste collection systems wherein a dissolvable solid bioactive element is submersed in the waste stream is described by Cline in U.S. Pat. No. 5,925,252. The dispensing of the active agent in this system relies solely on the dissolution of the solid bioactive element; therefore the rate of addition is not well controlled, since the rate of dissolution is greatly affected by external conditions such as temperature, pH and tonicity. Furthermore, such systems require the use of additives such as surfactants to produce the dissolvable solid bioactive element thereby limiting the scope of utilizable microorganisms.
A simple apparatus for treating drain runoff described by Richter et al. in U.S. Pat. No. 6,197,321 also relies solely on the dissolution of a solid bioactive element and therefore has the same limitations as the aforementioned U.S. Pat. No. 5,925,252. Furthermore, the device described by Richter reduces the receiving capacity of the drain and raises health and safety concerns regarding the placement, removal, and disposal of remnants. Additionally problems can arise due to misalignment and incorrect placement of the device resulting in resulting in blockage and activation failures.
Another deficiency associated with all of the direct contact methods described above is the requirement for ample direct access for the placement of the devices and attachment points for securing the devices. Also, since these systems provide little or no control of the release rate of active agents, the velocity of the waste stream rather than the level of contamination of the waste stream controls the release rate. For example, streams having high levels of contamination and low flow velocities release insufficient quantities of agent while streams having low levels of contamination with high waste stream flow velocity or volumes release excess quantities of agent. Another drawback of direct contact systems is premature surface activation which is an operational malfunction resulting from low flow conditions wherein a bio-coating forms on the surface of the solid agent resulting in encapsulation and thereby impeding the delivery of the active agent. Furthermore, these direct contact devices and systems often give unpredictable results when utilized in static, shallow, and surface waters and are not applicable to terrestrial environments.
A dispensing apparatus for introducing treatment material into an inceptor or grease trap for the purpose of digesting grease or other hazardous materials is disclosed by Heppenstall in U.S. Pat. No. 5,271,829. This apparatus is specific to grease traps and similar systems and is retrofitted to such systems by fixed attachment to the inside of the lid of the inceptor or grease trap. The dispensing apparatus of this system provides a porous rubber restrictor in the form of a flat disc located at the dispensing opening to providing a constant restricted dispensing rate. Such a restrictor may be prone to clogging during use. Also, the disclosed apparatus is limited to use with treatment solutions thereby precluding its use with remediation agents fixed to insoluble immobilizing media.
A bilge cleaner dispenser and method of dispensing liquid bilge cleaner is described by Clement in U.S. Pat. No. 6,152,331. This apparatus is used to treat trapped contamination contained in boat bilges and utilizes an orifice-type mechanical flow regulator to control the rate of addition of the liquid. Such orifice-type flow regulators suffer from a number of disadvantages and are prone to internal interruption and malfunctions caused by build-up from a migrating particulate-laden stream and from side products including bio-film associated with biological treatments. Furthermore the described apparatus is limited to use with only liquid cleaners thereby precluding use with remediation agents fixed to insoluble immobilizing media.
An apparatus for delivering activated microorganisms to an aqueous waste stream is described by Lucido et al. in U.S. Pat. No. 6,402,941. The apparatus is relatively complex in that it provides multiple containers each provided with independent pumping means. Furthermore, one container of the described apparatus is a bioreactor chamber in which the required organisms must be first grown prior to delivery. Another complex apparatus for delivering activated microorganisms to an aqueous waste stream is described by Lucido et al. in U.S. Pat. No. 5,840,182 wherein a multi-chambered bioreactor is operably connected a controller.
Remediation systems utilizing electrically powered components are well known in the art. However, electrically operated metering pumps, dispensing systems and delivery methods suffer from a numerous disadvantages. For example, potential safety hazards become obvious when utilizing electrical powered metering pumps requiring electrical interfaces in close proximity to drainage systems that often contain corrosive substance and sewer gas. Storm water drainage systems frequently receive vehicle fluids including oil and gasoline washed from surfaces into drainage systems by storm water and snow melt creating potentially dangerous conditions in proximity to electrical components. Therefore, due to increasing personal safety and insurance liability issues, many states and local jurisdictions have promulgate enforcement codes where only licensed personal are authorized to install, maintain, relocate or alter remediation systems utilizing electrical components. Finally, such electrical devices are often complicated and expensive to manufacture and maintain.
In view of the prior art there exists a need for a readily portable bioremediation apparatus capable of delivering predetermined, measured quantities of treatment agents, including microorganisms, to a wastewater stream continuously over time.
There exists also a need for a low-cost apparatus for the remediation or bioremediation of wastewater that is simple in construction and user friendly.
Furthermore, a need exists for apparatuses and methods for remediation or bioremediation of wastewater that are easily customized to address specific requirements for a given wastewater stream.
A still further need exists for apparatuses and methods for remediation or bioremediation of wastewater that dispense the treatment agents without the need for external power or electrical interface.
The devices and methods of the present invention address these and other needs.
Although the figures illustrate preferred embodiments of the invention they are intended to be merely exemplary and representative of certain embodiments. To that end, several figures contain optional features that need not be included in any particular embodiment of the invention and the shape, type, or particular configuration of the various elements of the apparatuses illustrated should not be regarded as limiting to the invention.